The present invention generally relates to optics. More specifically, the invention relates to systems and methods that involve the use of electron emitters for producing modulated light.
Optical systems, such as optical communication systems, are configured to propagate signals between various locations. Through at least a portion of such a communication system, the signals are provided as light beams that are propagated along an optical path. Such an optical path usually is defined by one or more communication links, each of which typically includes an optical fiber.
Modulated light sources typically are used to generate light beams for propagating through optical communication links. More specifically, a modulated laser typically is associated with each communication link for generating the light beams. By way of example, Vertical Cavity Surface-Emitting Lasers (VCSELs) have been used to generate modulated light beams.
A VCSEL typically includes a narrow aperture that characteristically provides a narrow beam of light at a short distance. The beam of light produced by a VCSEL also tends to diverge rapidly with increasing distance from the aperture. Therefore, it typically is necessary to ensure that an optical component that is intended to receive the beam of light from a VCSEL is placed close to the aperture of the VCSEL. Clearly, this requires a relatively high degree of precision to ensure that the optical component is aligned with the optical axis of the VCSEL because the optical component typically is receiving the narrow portion of the beam of light. As is known, ensuring proper placement of an optical component relative to a VCSEL can be time-consuming and/or expensive.
Use of VCSELs also can be problematic in some applications. In particular, VCSELs may not be suitable for use in applications in which a high degree of wavelength stability is required. This is because the wavelength of the light produced by a VCSEL tends to drift with temperature. Therefore, it should be appreciated that there is a need for improved systems and methods that address these and/or other perceived shortcomings of the prior art.
Optical systems of the invention include electron emitters for producing electrons. Electrical-to-optical converters of the optical systems receive the electrons and convert the electrons into light. The optical systems also modulate the light so that modulated light is emitted.
The electrical-to-optical converters include phosphorescent materials for generating light. The light generated by the phosphorescent materials is relatively omnidirectional and, therefore, precision alignment techniques may not be required when optical components are to be aligned for receiving the light. Additionally, the wavelength of the light generated by the phosphorescent material does not tend to vary with temperature. More specifically, phosphorescent material relies on atomic transitions to produce light and, therefore, is inherently relatively wavelength stable with respect to temperature.
In some embodiments, external modulation is used to modulate the light produced by the phosphorescent materials. By using external modulation, high speed modulation (high bandwidth) can be achieved. For example, in some embodiments, an electro-optic modulator, such as a thin film electro-optic element formed of LiNbO3, can be used to modulate the light externally.
Some embodiments of the optical systems also can be configured as integrated packages. By providing an integrated package for producing modulated light, difficulties associated with operatively aligning optical components at the location where the modulated light is required can be avoided. In particular, since the constituent components of the integrated package are operatively aligned with each other in a manufacturing environment, more precise alignment of the components can be achieved.
By using integrated packages, improved efficiencies in manufacturing also may be achieved. More specifically, the integrated packages may be well suited for manufacture by batch-processing techniques. For instance, in some embodiments, the electron emitter is supported by a first substrate, e.g., a substrate formed of a material suited for semiconductor fabrication, and the electrical-to-optical converter and external modulator are supported by a second substrate. The first and second substrates then can be fixed in position relative to each other, such as by a bonding operation.
In some embodiments, the electron emitter and electrical-to-optical converter can be arranged within a cavity formed by the integrated package. Advantageously, the integrated package provides a protective enclosure for the components arranged within the cavity, thereby improving system robustness. Additionally, the cavity can be hermetically sealed to reduce the potential for degradation of device performance due to contamination, for example. The cavity also can be evacuated in some embodiments to facilitate proper operation of the electron emitter.
A representative method of the invention for producing modulated light includes: producing a beam of electrons; converting the beam of electrons into light; and modulating the light.
Clearly, some embodiments of the invention may not exhibit one or more of the advantages and/or properties set forth above. Additionally, other systems, methods, features and/or advantages of the present invention will be or may become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional systems, methods, features, and/or advantages be included within this description, be within the scope of the present invention, and be protected by the accompanying claims.